First impression of the Diablo out of the box is that it is extremely user friendly. The operator manual supplied from the factory excellently prepares you to use the tuner and to prepare the truck for both the stock down load from the truck ECM and the performance upload of the Diablo tune. If you follow the Diablo display prompts and remove the fuses for your model year, it's almost impossible to mess up.

I chose the "87 Octane" power/ performance and economy tune. I still have about a half a load of 87 octane on, so thus the choice. I installed the 87 "As is" Diablo tune. You have the option to tweak specific paramaters within the 87 tune, but I opted to install it as is.

I started at the bottom of what's available so I can compare the hotter tunes they offer once I have 93 in the tank.

I fired it up after the install and immediately noticed slightly higher smoother idle, instant gear engagement, the raised shift points, pronounced shifts and crisp kickdown function. Then came the foot to the floor test.....Shift point is now approx. 5500! It's pulling to the moon! When I let out of it, it was still pulling! Launching from a dead stop spun the tires for about 5-6 feet and no bog....Just lots of giddy up torque! It's a different truck! And this is the 87 octane tune that can still be tweaked!

Based on posts read here from the guys talking about the installation of the forward Corvette servo assy., I ended up placing an order with Oregon Performance Transmission for the 1-2 / 2-3 Corvette servo, the billet 4th gearapply/lockup support servo, Transgo shift kit and seperator plate, plungerless accumulator piston assy.for the valve body that further improves the 1-2 / 2-3 shift and the proprietary plunger valve and ball assy. that improves crucial oiling, oil anti-drain back and further improves1-2 / 2-3 shift timing also that better syncronizes the apply and release of the servos that apply the bands and clutches between shifts.

I figured that based on the mileage on the truck and the moderate towing I do, these were the most beneficial improvements I could make to get maximum service life out of the trans. before doing any harm to it in the stock form, particularly now that the motor is throwing some serious azzzz at it. Can't wait to get the trans parts and get started. I'm debating on a +3 qt. capacity deep pan to go along with the Corvette filter and deeper pan adapter and drain plug kit. Of course I'll do the fluid change at the same time.

I also run the 87tune in my 05 Z-71. The best adjustment I made was to dial-in the long term fuel trim (LTFTs). Go on ther e website and it explains how to do this. Follow there directions, it my take afew adjustments but you will be happy with the adjustments. Your truck will have better throttle response than now and will be alot faster.

To adjust the ltft, first you have to go to the live data on the programmer and drive per the instructions on there website. Dont worry about the short term fuel trims, you drive until the ltft lock in (stop adjusting) They will not be the same for each side, this is normal. They may start adjusting themselves if you go up or down a hill, but just drive until they lockin again. They should be between 0 and -2. If you have to adjust pull over and shut off your engine and go to the modify tune and scrool down to injector slope and press enter and you will see + or -. Dont go crazy, adjust in small incraments and go back into your live data and do another test run. Sometimes you get the adjustment the first time and sometimes it takes a few trys. If your ltft is in the plus than go to the minus on your adjustments and if there in the plus than go to the negative. GMs are usually on the plus side. Mine was in the 9.00 plus side so I ended up taking 8% out and now Im at 0 on one side and 1.25 on the other side. Make sure you drive between 1,800 and 2,400 rpms at a steady speed , if you have cruise control that makes it easy and if you can drive on a flat road that lets the ltft lockin sooner. The engine has to be good and warm and it take between 20-30minutes of steady driving to get the ltft to lockin. I know this looks like alot but its not that bad and the payoff is worth it. Basicly what you are doing is tricking the computer into thinking it has differant size injecters. Hope this helps, just take your time and have fun with it.

thanks for the detailed instructions! i remember when i bought the programmer from SLP, they gained 40hp on the 6.0 liter motor, and i think it was from doing this adjustment. hopefully, i can get a few more. By the way, i just saw F.A.S.T. is coming out with a new intake manifold that is said to add 40hp with no other mods, its called the LSXrt. i'm sure its pricey but thats a huge increse on the 5.3

Hadn't been back to the Diablo site yet, but this trim information is good stuff...It just keeps getting better! Thanks for the trim heads-up! I just finished waxing the whole truck. That ought to be worth another 1-2 mpg too....LOL :rofl:

jbfieemt, The LSX manifolds wont fit the trucks unless you change the front assecary drive mount and have or install electric fans because the shorter manifold will make the throttle body hit the front accessary drive bracket.

To adjust the ltft, first you have to go to the live data on the programmer and drive per the instructions on there website. Dont worry about the short term fuel trims, you drive until the ltft lock in (stop adjusting) They will not be the same for each side, this is normal. They may start adjusting themselves if you go up or down a hill, but just drive until they lockin again. They should be between 0 and -2. If you have to adjust pull over and shut off your engine and go to the modify tune and scrool down to injector slope and press enter and you will see + or -. Dont go crazy, adjust in small incraments and go back into your live data and do another test run. Sometimes you get the adjustment the first time and sometimes it takes a few trys. If your ltft is in the plus than go to the minus on your adjustments and if there in the plus than go to the negative. GMs are usually on the plus side. Mine was in the 9.00 plus side so I ended up taking 8% out and now Im at 0 on one side and 1.25 on the other side. Make sure you drive between 1,800 and 2,400 rpms at a steady speed , if you have cruise control that makes it easy and if you can drive on a flat road that lets the ltft lockin sooner. The engine has to be good and warm and it take between 20-30minutes of steady driving to get the ltft to lockin. I know this looks like alot but its not that bad and the payoff is worth it. Basicly what you are doing is tricking the computer into thinking it has differant size injecters. Hope this helps, just take your time and have fun with it.

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Wondering where the specific LIFT adjustment link is on the website? Can't seem to locate it. Maybe looking right at it but don't see it. Appreciate your help.

Go to the product section and enteryour info, it will show in red lettering Detail How To Adjust Parameters, click-on and scoll down to Injector Slope and it says Determaning LTFTs. To adjust your LTFTs on your programmer go to modify tune and scroll down to injector slope and there is where you adjust your LTFTs